Drawing tube



1942- J. J. PONCAR DRAWING TUBE Filed Dec. 13, 1941 2 Sheets-Sheet l J. J. PONCAR DRAWING TUBE Dec. 29, 1942.

Filed Dec. 13, 1941 2 Sheets-Sheet 2 Patented Dec. 29, 1942 7 DRAWING TUBE John J. Poncar, Cleveland, Ohio, asslgnor to Chase Brass & Copper 00. Incorporated,

Waterbury, Conn, a corporation Application December 13, 1941, Serial No. 422,858

2 Claims.

This invention relates to improvements in means for drawing tubes with dies and floating plugs.

One object of this invention is to provide an improved floating-plug construction employing an elongated rod secured to and extending rearwardly from the floating-plug, the rod being supported by the draw-bench but not being subjected to tension by the floating-plug during the drawing operation.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings forming part of the present disclosure, in which one way of carrying out the invention is shown for illustrative purposes:

Figs. 1a and 1b are side elevations of contiguous portions of a draw-bench, die and floatingplug and rod in accordance with the present invention;

Fig. 2 is a fragmentai cross-sectional view on line 2-2 of Fig. 1a;

Fig. 3 is a cross-sectional view on line 3-3 of Fig. 1b;

Fig. 4 is a rear elevation of the floating-plug with the rod removed therefrom;

Fig. 5 is a side elevation of the floating-plug shown in Fig. 4; and

Fig. 6 is a perspective view of the floating-plug assembled with the rod.

In the description and claims, the various parts and steps are identified by specific names for convenience, but they are intended to be as generic in their application as the prior art will permit.

Referring to the drawings, a draw-bench or draw-bench construction In including a trough II and having a drive-chain l2 for moving the draw-carriage l3, all of usual construction may be employed. A die 14 is mounted on the drawbench for drawing a tube I5 therethrough by means of the carriage l3 in a well-known manner.

Within the die and tube to be drawn is placed a floating-plug l6, screwed into the rear end of which is an elongated rod H which extends rearwardly through the end of the tube l5 and is supported by engaging-means such as the tail-stock l8 at the rear of the draw-bench. A removable pin l 9 serves to restrain the rear portion of the rod I! from being thrown up out of the crotch of the tail-stock l8 during the drawing operation, but permits longitudinal sliding movement of the rod ll axially of itself both forwardly and rearwardly, within the limits of play of the head 20 of the rod ll between the walls 2| and 22. The head 20 provides ample area on its rear face to take the blow against the wall 2| which occurs due to the violent longitudinally-backward movement of the rod I1 and floating-plug l6 which occurs at the moment that the rear end of the tube being drawn passes through the die It.

Due to one or more of various causes well known to those skilled in the art, imperfections of the inside surface of tubes, and the lack of perfectly uniform thickness of tubes at all points, result at times in setting up at least two general types of vibration or oscillation in floating-plugs with consequent failure to rectify the imperfections or inequalities of the tubes being drawn, and even into bringing about exaggeration of such defects or producing other defects. Thus, for example, if successive longitudinally-aligned portions of a tube being drawn, vary in thickness from thin to thick to thin and so on, this tends to bring about an angular vibration or whipping action of the floating-plug with consequent marring, or production of further defects in the inside of the tube being drawn. Also, if successive annular or diametrically-opposite portions of the tube being drawn, vary in thickness or internal diameter so that the internal diameter changes from small to large to small and. so on, this tends to induce in the floating-plug an axial back-and-forth vibrating action which tends to the production of additional defects in the tube.

By my improved floating-plug construction in which I provide a rod secured to and extending axially rearwardly from the floating-plug proper, and support the rear portion or end of the rod at a location in approximate axial alignment with the die and free for ample longitudinal movement, both of the foregoing whipping or vibrating actions of the floating-plug are in large measure overcome. Thus, the mass of the rod l1 plus its stiffness and the fact of its rear end being anchored against substantial transversemovement, results in a definite inhibiting action to angular oscillation or vibration of the floating-plug. Also, the mass of the rod ll has a damping action and inhibits longitudinal axial vibration of the floating-plug proper, that has been previously described.

Inasmuch as the rod I1 is not subjected to any tension by the drawing operation, a single rod of moderate size can be used interchangeably with a number of different sizes floating-plugs by virtue of the detachable screw-threaded connection. The rod I! also facilitates the insertion of the floating-plug into drawing position in the tube by the operator merely grasping the rod carrying the floating-plug and shoving them endwise into the tube to be drawn.

The invention may be carried out in other speciflc ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. Tube-drawing means comprising: a draw: bench; a tube-drawing die mounted on said drawbench; a floating-plug for use inside of a tube being drawn through said die; and an elongated rod fixedly secured to and extending rearwardly from said floating-plug; engaging-means on said draw-bench supporting the rear portion of said rod; said rod being free to move longitudinally forward sufllciently to permit said floating-plug to remain seated in drawing position against the inner portion of the tube being drawn without imposing tension on said rod, throughout the operationo'f drawing the tube through said die; and means for pull-drawing a tube through said tube-drawing die in front of said tube-drawing die.

2. Tube-drawing means comprising: a drawbench; a tube-drawing die mounted on said drawbench; a floating-plug for use inside of a tube being drawn through said die; and an elongated rod fixedly secured to and extending rearwardly from said floating-plug; engaging-means on said draw-bench supporting the rear portion of said rod, and restraining said rear portion from substantial transverse movement; said rod being free to move longitudinally forward suiiiciently to permit said floating-plug to remain seated in drawing position against the inner portion of the tube being drawn without imposing tension on said rod, throughout the operation of drawing the tube through said die; and means for pull-drawing a tube through said tube-drawing die in front of said tubedrawing die.

.JOHN J. PONCAR. 

